Actor Tommy Lee Jones put in such a realistic portrayal of Douglas Macarthur it was like having the famed war general on set, according to his co-star Matthew Fox.

The Men in Black star takes the role of the iconic World War Ii U.S. Army officer in hard-hitting military drama Emperor, and Fox, who plays a fellow leader in the film, was stunned at his colleague's performance.

Fox has revealed most of the shoot had been completed before Jones arrived to film his scenes, and his acting was so lifelike the cast and crew were convinced the real general was on set.

Fox tells U.K. morning show Daybreak, "I felt that there was no other actor I could imagine playing MACArthur. MACArthur is such an iconic military figure for Americans in the 20th Century and so I really felt that he was the perfect guy to play him and was going to bring a gravitas to that role. I really enjoyed it.

"He came at the end of the shoot so we had shot a huge portion of the film, and it was really like MACArthur was showing up in our world."

General MACArthur was an instrumental figure in the U.S.' military campaign in the Pacific and oversaw the surrender of Japan in 1945, which marked the end of World War Ii.